Tex, I listed a dozen of characteristics of why JBP make superior bonsai.
I've never seen a pinus patula bonsai. Doesn't mean there aren't any, I just haven't seen any.
But, the drooping (or weeping) foliage is problematic. Usually we don't use trees that grow that way for bonsai, except as a novelty. Weeping willow comes to mind. Hardly ever see one as bonsai.
I listed the JBP traits earlier.
For bonsai, the things that made a species desirable are (in no particular order): The tree can be made to look like an old tree at an early age, the tree is long lived, the foliage is in scale with the tree, it's easy to build sizeable trunks, the tree has short internodes, ramification is easy to achieve, the tree tolerates living in a container, the tree tolerates root work, the tree tolerates frequent pruning, the tree tolerates wiring, the tree does not randomly sluff off branches, the tree heals scars well, the tree is relatively insect resistant and disease resistant, and the tree is relatively adapatable for living at different climate zones.
There's probably more, but that's what I came up with on the fly.
Now, with the JBP in particular, the tree has been cultivated as bonsai for centuries. The hows, why's and wherefore's are well documented. With the following caveat: There is a lot of MIS-information out there as well. Well meaning people may pass on erroneous information without realizing it. Which confuses people. Particularly beginners. Older books do not have the current techniques. So, lots of people go to the library for information about bonsai when they first get started. And check out books. And those books may be outdated.
I recommend to anyone just getting started with JBP begin by reading Brian Van Fleet's excellent on-line book at
www.nebaribonsai.com. He has documented the process with words and pictures, and following his program is an excellent way to start!